The present invention relates to a sputtering apparatus used for manufacturing, for example, various types of semiconductor devices, magnetic devices, electronic parts and optical components, and a method of manufacturing a solar battery and an image display device by using the sputtering apparatus.
Sputtering is a thin film forming process in which plasma is generated in rare gas such as Ar (argon), krypton (Kr) or xenon (Xe), ions of the rare gas collide with a target to expel the target substance, and the target substance is deposited as a thin film on a substrate. At present, argon gas is mostly used as the sputtering gas. Accordingly, description is made using Ar as the sputtering gas in this specification, but it is needless to say that the same manner can be applied to a sputtering apparatus using another rare gas. And, to improve a film-forming speed on the substrate, magnetron sputtering has a magnet device on the back side of the target to generate a required magnetic field near the surface of the target, thereby enhancing a plasma density.
A sputtering apparatus having a flat-shaped target is mainly used for production of semiconductors and electronic parts. Especially, for a flat panel display (FPD) among the electronic parts, a sputtering apparatus provided with a sputtering cathode of a rectangular magnetron method is used to form electrodes and wires. As the FPD, there are a liquid crystal display, a plasma display, an organic EL display and the like. In recent years, the FPD is becoming large, and the sputtering apparatus is being required to deposit a thin film on a large-area substrate.
There are generally two methods of sputtering for film formation on a large substrate.
One of them is a batch system by which a large target or a split target is sputtered with a substrate in a stationary state, and the sputtered particles flying from the sputtered target are adhered onto the film-forming surface of the substrate to form a film on it.
The other is a continuous system by which a long and thin target whose longitudinal direction is directed to a transverse direction of the conveying direction is sputtered while conveying a substrate on which a film is to be formed, and the sputtered particles being flying from the target are adhered onto the film-forming surface of the substrate to form a film on it. This long and thin target may have a rectangular or cylindrical shape.
Either of the above systems positions the target at the front with respect to the substrate, so that its film-forming speed is high, but the substrate and the film being produced are directly influenced by radiation heat of plasma. By configuring in this way, ions having high energy hit the target, the target particles flown out by the energy enter the substrate surface, and other recoil neutral particles and others collide with the substrate to damage the film.
Therefore, there is conventionally proposed the sputtering apparatus of an obliquely opposed target method as described in JP-A 1-108369 (KOKAI). Specifically, there is a known sputtering apparatus which has plural targets arranged to obliquely face the substrate and other targets. This sputtering apparatus of the obliquely opposed target method improves a film-forming speed by utilizing the fact that the number of particles flying out in an oblique direction with respect to the normal of the target surface is many.